Senator Franken gives his fellow Democrats a lesson in showing a spine.

Sen. Al Franken (D-MN) said on Tuesday he would test whether a Senate tradition that his Republican colleagues used to thwart several of President Obama’s judicial nominees will actually be honored now that Donald Trump is in the White House.

A quick primer. When Democrats controlled the Senate, and Sen. Pat Leahy (D-VT) chaired the Judiciary Committee, Leahy would not allow a judicial nomination to move forward unless both of the nominee’s home-state senators returned a “blue slip” agreeing to let the nominee have a hearing. Senate Republicans used this ability to block several of Obama’s judges. Franken has now decided to test whether current Senate Judiciary Chair Chuck Grassley (R-IA) will do Democratic senators the same favor.

!!!! @alfranken says he won't return blue slip for Stras, Trump's nominee for a seat on the Eighth Circuit

In effect, Franken is trying to veto Trump’s nomination of Minnesota Supreme Court Justice David Stras to a federal appeals court, noting his fear that Stras will “steer the already conservative Eighth Circuit even further to the right.” Stras is a former law clerk to conservative Justice Clarence Thomas, who typically hires ideologically similar young lawyers to work in his chambers.

Last month, Sens. Debbie Stabenow (D-MI) and Gary Peters (D-MI) decided not to force a blue slip confrontation against another Trump nominee, a former law clerk to conservative Justice Antonin Scalia.

Though Leahy permitted even a single Republican home-state senator to veto a nominee, past judiciary chairs typically have not been so tolerant of such efforts to block nominees.

In any event, Franken’s decision not to return a blue slip on Stras guarantees either a short-term victory or a long-term win for Democrats. Either Grassley honors Franken’s veto, in which case a very conservative Trump nominee is kept off the bench. Or Grassley doesn’t, in which case Democrats get an unambiguous lesson that the blue slip isn’t going to be there for them, so maybe it shouldn’t stick around when Democrats control the White House either.

That won’t keep Staus off the bench, but it will most likely prevent a repeat of the pattern in the Obama years, when Republicans blocked the president’s nominees with impunity.